Mining machine chain cutter



April 7, 1936. '.F.L.FULKE MINING MACHINE CHAIN CUTTER Filed June 12, 1935 2 Sheets-Sheet 1 5 [N vE/v'roR:

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April 7, 1936. F. FULKE MINING ACHINE CHAIN CUTTER Filed June 12, 1933 -2 Sheets-Sheet 2 ATT'Y Patented Apr. 7, 1936 PATENT- OFFICE I 2,036,573 MINING moms mm co'r'rna Frank L. Fulke, Terre Hautc, 1116., assignor to The Jeffrey Manufacturing Company, a corporation of Ohio Application June 12, 1933, Serial No. 675,419

54 Claims.

My invention relates to chain cutters adapted for use in coal mining machines, and one of the objects of the invention is the provision of improved and eflicient bit holding links having seats successively inclined at different angles transversely of the chain for the mounting of mechanism for holding bits at corresponding angles relative to the path of travel of the chain.

A further object of the invention is the provision of right-handed and left-handed bit holding links extending from opposite sides of the chain, those of the right-handed type being castings of similar shape and size and those of the left-handed type also being castings of similar shape and size and each casting being adapted to have milled transversely thereof a seat for mechanism to hold a bit at an adjusted angle. whereby the successive bits on the chain will be mounted at gradually varying angles along the entire chain.

Another object of the invention is the provision of improved mechanism comprising transverse seats on successive bit holding links at succes sively varied angles relative to the path of travel of the chain, for mounting bits at successively varied angles.

A further object of the invention is the provision of improved mechanism for holding a cutter bit in adjusted position on a bit holding link on an axis offset from the path of travel of the chain and parallel thereto.

Another object of the invention is the provision of a cutter bit with cutting edges extending laterally therefrom to cut away sufiicient material from the kerf being cut to prevent abrasion or wear of the bit holding link itself.

A further object of the invention is the provision of a multiple cutter bit having a plurality of cutting points spaced apart from each other suecessively with suflicient metal between the same to facilitate drop forging in manufacturing the multiple cutter bit; by strengthening the connections between the points and at the same time forming such reinforcing metal with cutting edges adapted to prevent the mineral in the vein from coming in contact with the bit holding link thereby preventing wear of the latter during kerf-cutting operations.

Another object of the invention is the provision in a bit holder of a rotatable clamping element having means for interlocking the same with another clamping member when the bit is in operative position.

A further object of the invention is the provi-, sion of limit stops for the rotary member of a bit holder.

Another object of the invention is the provision in hit holding mechanism of an improved seat for one side ofa multiple cutter bit the opposite side of which is smooth and approximately fiat, to prevent rotation of said multiple cutter bit during 5 operation of the chain cutter.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

For the purpose of disclosing my invention I 10 have illustrated certain embodiments thereof in the accompanying drawings in which Fig. 1 is a side elevation of a. chain cutter embodying my improved form of multiple bit and the mechanism for securing the same to the bit 15 links;

Fig. 2 is a sectional view taken on the line 2-1 of Fig. 1 looking in the direction of the arrows and showing the bits of the successive links in various adjusted positions;

Fig. 3 is a perspective view of one of the righthanded bit holding links;

Fig. 4 is an enlarged sectional elevation of the bit holding mechanism mounted on a bit holding 25 link;

Fig. 5 is a side elevation of the left-hand or front member of the bit holding mechanism shown in section in Fig. 4;

Fig. 6 is a perspective view of said left-hand or front member of the bit holding mechanism 30 shown in Fig. 4;

Fig. 7 is a front view of the flat side of the multiple bit which is shown in star formation;

Fig. 8 is a rear view of the bit shown in Fig. 7;

Fig. 9 is a side view of the bit of Fig. '1;

Fig. 10 is a section taken on the line l0l0 of Fig. 1 looking in the direction of the arrows showing the rear views of the bits of the successive links in various adjusted positions;

Fig. 11 is a sectional elevation taken on the line II-IZ of Fig. 1 with all of the bit holding mechanisms removed to show the successively inclined seats on the bit holding links;

Fig. 12 is a front view of the rear or right hand bit holding element shown in section in Fig. 4;

Fig. 13 is a side view of the element shown in Fig. 12; and

Fig. 14 shows a modified bit holding link and modified bit holding mechanism for the star bit 9 shown in Figs. '7, 8 and 9.

In the embodiment shown in Figs. 1 to 13, inclusive, the bit carrying link I5 is provided with bit carrying heads, those designated 16 being right-handed in projecting to one side of the ,Each head is laterally offset either right-handedly or left-handedly and each is preferably tapered rearwardly as shown at l6 in Figs. 3 and 4. Each head is arranged at the rear end of the link, being cast integrally therewith. All of the right-handed linksalways remain on one side of the chain and all of the left-handed links always remain on the opposite side of the chain. The bit holding links l5 are connected together by connecting links l8 and pintles 59. To provide such connections each of the bit holding links is provided with pivot pin openings 20, 20 extending therethrough and into which the connecting pins or pintles are adapted to pass.

Each of the offset heads l6, I1 is centrally bored at 2| on axes parallel to the medial plane extending vertically through the center of the chain, such parallel axes being spaced laterally from such medial plane. Each bore 2| is screwthreaded at- 22 to receive the screw-threaded end portion 23 of a bolt-24 the head 25 of which is provided with a collar 26 which is adapted to engage the front clamping member 21 as shown in Fig, 4. 'If desired the opening through the head may be a smooth bore and the opening 60 threaded to receive the bolt 24 turned end for end from its positionin Fig. 4. The rear clamping member 28 is provided with a flat face: 29 which is adapted to rest onthe flat seat 39 on the head Hi. The width of the seat 30 measured longitudinally of the bore 30 is equal to the width of the lower fiat face 29 similarly measured.

Consequently when the parts are assembled asshown in Fig. 4 the upper and lower flat faces 3| and 32 respectively above and below the horizontal flat face 29, fit snugly against the vertical faces 33 and 34 on the head |6 as shown in Figs. 3 and 4. When the parts are assembled.

as shown in Fig. 4 the faces 3|, 29 and 32 engage respectively the face 33, the seat 30 and the face 34 on the head l6, the faces 3|, 33 and 32, 34 being in planes at right angles to the axis of the bolt 24 and thefaces 29. 33 beingin a plane parallel to such axis and spaced therefrom.

The clamping member 28 is recessed at its upper: tapering portion as shown in Figs. 4 and. 12 to receive the rear side of the star-shaped cutting bit 35. The recess in the front face of the clamping member 28 is formed to correspond to the rear formation of the multiple pointed bit shown in Fig. 8. From the center 36 of the hit three radial ribs 31, 38, 39 extend to three equidistant cutting points 40, 4| and 42. The front face 43 of the cutter bit is approximately fiat. In drop forging a metal blank, inclined walls 44, 45, 46, 41, 48 and 40 are extended from the radial ribs 31, 38 and 39 to the V-shaped cutting edges 50, 5|, 52, 53, 54 and 55. Sufflcient metal is included in the blank to form the reinforcing connecting cutters'56, 51, 58 between each pair of adjacent V-shaped cutter bits. Not only do the reinforcements at 56, 51, 58 facilitate drop forging by maintaining the star bit integral and homogeneous throughout but their edges at the flat surface 43 have a cutting action to provide ample clearance for the offset head on the bit holding link thereby preventing the head from becoming worn by contact with the coal in the mine vein.

The front clamping member 21 is provided with a rear inclined flat face 59 which as shown in Fig. 4 is adapted to engage the front fiat face 43 of the star bit in a plane sloping in the direction of travel of the chain cutter. The bolts 24 extend through the opening 60 in the front clamping member 21 and through the opening 60 in the rear clamping member 28 and when the bolt is screwed in place as shown in Fig. 4 the collar 26 clamps the members 21, 28 against the head l6 while the bit 35 is clamped in adjusted v between the clamping members 21 and 28.

By referring to Figs. 8 and 9 it will be seen that from the central portion 36 of the rear side of the multiple bit the radial ribs are parallel to the fiat face 43. These straight radiating ribs are adapted to fit into the radial recesses 6|,

vent wear by abrasion of the bit holding link II by compelling the renewable and adjustable bit to cut ample clearance for free travel of the chain. 7

When a bit point becomes dull due to wear it may be adjusted to an inoperative position and replaced by an unused bit point. For instance if the point 42 of Fig. 8 becomes worn it may be replaced by the point 40 or 4| by simply loosening the front clamp 21 and rotating the star bit 120 relatively to its back seat on the clamping member 28.

To reinforce the front clamping member 21 it may be provided with a vertical radial rib 61 as shown in Figs. 2, 4, and 5. 'To assure proper positioning of the front clamping member 21 relative to the rear clamping member 28 when the parts are assembled as shown in Fig. 4 a lower rear lug or tongue 68 on the clamping member 21 is adapted to fit into a corresponding recess or groove 69 in the lower front. face of the rear clamping member. When the bit is clamped to the head l6 the-tongue and groove connection at 68, 69 interlocks the clamping members 21, 28 and prevents relative rotation between the clamping members during operation of the chain cutter.

The rear face of the clamping member 21 is cut away at 10, 1| to provide ample space for-the limit stops 12, 13. When the bolt 24 is sufllciently released the front clamping member 21 may be turned 90 in either direction or until the lug 68 strikes against one of the limit stops 12, 13 whereupon the cutter bit may be readjusted, the lug 68 replaced in the recess 69 and the bolt re-tightened. The limit stops serve to indicate the extent of rotation of the clamping member 21 desirable to save time in readjusting a large number of cutter bits of chain cutters.

The rear inclined faces 10 and 1| serve to afiord ample room for the multiple bit to be tilted from the socket on the bit clamping member 28, when either inclined surface 10 or 1| is brought into proximity to the front face 43 of the multiple bit 35. The bolt 23 need be released only to a small extent by a partial turn thereof to enable the lug 68 to be withdrawn from the recess 69, whereportion Hi is in proximity to the front face 43 of the multiple bit 35, the latter may be tilted forwardly out of the socket of the clamping member 28. Consequently, considerable time will be saved by reason of the fact that with a minimum releasing movement of the bolt from the socket the front clamping member 2'! may be moved to hit releasing position either in one direction or the other, there being inclined faces 10 and H on opposite sides of the front clamping member 21, as shown in Fig. 6. As the front clamping member has its lug 68 resting against the limit stops 12 or 13, one of the inclined surfaces 10 or H is adjacent the cutter bit and the latter may be quickly removed with another or unused cutting point in cutting position, whereupon the parts may be replaced and tightened to their positions shown in Fig. 4. I

It should be particularly noted that all of the bit holding links having the right-hand heads ii are castings similar in size and shape and all of the bit holding links having the left-hand heads ll are castings of similar size and shape. Only two sets of castings for the chain cutter are therefore provided. The seats 30 illustrated in Fig. 3 are preferably formed on such castings by milling operations. It is desirable to reduce the castings to a minimum number by milling the seats 20 at the desired angles on the successive links.

As shown in Fig. 11 the seats 30 on the successive bit holding links having the right-hand heads l6 are successively inclined at different angles so that when the bits are mounted in position they will have their cutting points located at increasing distances from the vertical medial plane of the chain. Fig. 11 also shows the variation of the angles of the seats 30' on the heads H of another series of bit holding links.

By reason of the variation in angularity of the successive seats 30 and 30 along the chain the assembled structure will appear as shown in Fig.

' lation' when viewed endwise of the chain or along'the kerf being cut and in like manner the points 40, 40', 40, 40 and III will occupy a fan-shaped relation when viewed likewise. The width of the kerf cut will be the distance between the points 40 and 42.

Each series of hit points on the,respective heads 18 and I1 form a uniform spiral with the points equidistant from each other as viewed in Fig. 2

or Fig. 10 but the distance between the two series, that is, between the points 40 and 42 is approximately twice as great. Thus a larger space is provided at I4 along the whole chain cutter so that the cuttings will be increased in size without decreasing the efficiency of the chain cutter in producing the desired kerf. By the inclusion of larger lumps in the cuttings the value of the latter is increased when screened, cleaned or otherwise treated for the market.

In the modification shown in Fig. 14 the bit holding link i" is provided with abutments l5 and 16 between which the bit clamping members 21" and 28' are adapted to be inserted. These clamping members are not provided with openings there-thru because instead of the bolt 24 of the form shown in Fig. 4 a set screw 11 is provided with a conical point I8 to fit into a conical recess 19 in the front face of the clamping member 21. The rear side of the clamping member 28' is provided with a circular projection 80 which fits into a corresponding recess, there being no opening extending through the block 15. The transverse face 29 of the rear clamping member 28' fits on a transverse seat 30 the angularity of which varies on succeeding links. By screw-threading the set screw 11 through the opening in the block 16- the bit holding mechanism may be firmly held in clamping position and by partially retracting the set screw the front clamping member 21' may be partially rotated on the conical point 18 as a fulcrum when the points of the bit are to be readjusted or a new star bit is to be inserted in place.

It will be evident from the foregoing that in the mining machine chain cutter shown and described all of the bits are alike and in each bit holding device the clamping members and bolts are respectively alike. Only two types of bit link castings are necessary one with the righthanded heads and the other with the left-handed heads. The transverse seats 20 formed by milling are varied as to their angularity so as to hold the cutter points in spiral formation or fan-'- shaped relation. It is preferred to spiral the cutting points in clockwise direction on the two offset axes extending longitudinally of the centers of the bolts 24, so that the spiral formation will extend continuously from one side of the chain to the other side thereof as shown in Fig. 2 and consequently in operation of the chain cutter this spiral formation extends from one wall of the keri' to the opposite wall.

However, if desired, the chain may be assembled to distribute the transverse seats so that the cutting points will succeed each other along the chain'in staggered relation relative to the path of travel of the chain cutter.

While I prefer to employ two types of bit holding link castings and. mill the transverse seats 20 thereon, the clamping member 2! may be cast integral with the body of the bit holding link if desired but in that event many different castings would be necessary to secure the formations of the bit points shown in Fig. 2. Furthermore, it is desirable to construct the clamping members of stronger metal than the bodies of the bit holding links and I therefore prefer to manufacture the clamping members separately.

The flanges or keys ll, 82 are adapted to travel along guides at the edge of a cutter bar and the arrangement of the cutting points is such as to cut sufficient clearance for free movement of the cutter bar in the kerf. Where a relatively thincutter is used the spread of the cutting points need not be as great as that shown in Fig. 2. Therefore, when a relatively thin cuttel bar is used the bit holding links may all be cast alike with the projecting heads centrally located with the axes of their bores in the medial plane of the chain cutter. In that event the transverse millings to produce the seats corresponding to that designated 30 in Fig. 3 may be performed on successive bit holding links to secure a uniform spiralling of the cutter points from one side of the chain to the other side with as many points in each formation as may be desired.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I wish therefore not to be restricted to the precise construction herein disclosed. 7

Having thus disclosed an embodiment of my invention what I desire to secure by Letters Patent of the United States is: 1 q 1. In a bit holder for mining machine chain cutters, the combination with a chain link having a projecting extension provided with a longitudinally extending opening, of a transversely extending seat on said extension, 9. pair of bit clamps one of which is adapted to engage said seat, a. bit adapted to fit, between said clamps, and a bolt extending through said clamps and into said opening to secure said bit between said clamps and secure one of said clamps to said seat.

2. In a bit holder for mining machine chain cutters, the combination with a bit holding link having a projecting support with a transverse seat thereon, a pair of clamping members one of which is adapted to fit said seat in non-rotatable position and the other of which is rotatable relatively thereto" for adjustment, 9. bit iltting between said clamping members, and means for securing said clamping members and said bit in rigid connection to said seat and said bit holding link.

3. A bit for cutter chains having a plurality of spaced-apart radially disposed points connected together by cutting edges substantially outlining a triangular contour, and a plurality of arcuate wedge shaped projections on one side of said hit.

4. A bitfor cutter chains having a plurality of spaced-apart radially disposed points having straight cutting edges extending therefrom with curved cutting edges connecting said straight cut-- ting edges substantially outlining a symmetrical contour.

5. A bit for cutter chains having a substantialiy flat front face, with a plurality of cutting points equidistant from each other and the center of the bit, the back face of said bit having ribs radiating from the center of the bit to said points and said ribs having a spaced-apart pair of flaring faces, one pair individual to each rib.

6. In a chain cut-tor for mining machines, the combination with a bit holding link, of a projecting head on said link and formed with a screwthreaded opening therein, a pair of clamping members each-having an opening therethrc-ugh adapted to register with the opening in said head, a multiple pointed bit adapted to be mounted. between said clamping members for rotary adjustment relative thereto, and a bolt having a. collar engaging one of said clamping members and passing through the openings in both and screw-threaded into the opening in said head to hold said clamping members and said bit rigidly connected to said head during operation of the chain cutter.

7. A drop forged bit for cutter chains, integral throughout and comprising equidistant spacedapart cutting points connected on one side of the bit by radial ribs with inclined faces extending therefrom to-triangular faces located midway between the points.

8. In a chain cutter for mining machines, the combination with a chain comprising a plurality of bit holding links cast similarly in shape and size and having seats milled transrersely thereof at various angles and spirally in succession along the chain, a plurality of bits onefor each of said bit holders. and bit holding devices secured to said seats to hold said bits in predetermined forone side of the chain to the other.

10. In a chain cutter for mining machines, the combination with a bit. holding link havi spaced apart abutment blocks, of a set screw threaded through one of said abutment blocks and having a conical end located between said abutment blocks, and bit holding mechanism comprising two clamping members one seated on one of said abutment blocks for non-rotation relatively thereto and the other having a conical recess for receiving the conical end of said set screw, said other clamping member being rotatable on said conical end relatively to the link without detachment therefrom.

11. In a chain cutter for mining machines, the combination with a plurality of connected bit holding links, of right-handed heads on some of the bit holding links and left-handed heads on other bit-holding links, transverse seats on said heads successively in spiral formation along the chain with respect to the right-handed heads and successively in spiral formation along the chain with respect to the left-handed heads,iand bit holding mechanism on said heads and adjustable on longitudinal axes spaced laterally from a medial lane extending through the path'of travel of the chain.

12. A bit for cutter chains provided with a plurality of cutting points radially disposed and having,cutting edges extending inwardly from said points, the back of said bit having angular I faces extending from the central portion of said bit to said cutting edges, and reinforcements between the inner ends of said cutting edges.

13. A bit for cutter chains having a substantially' flat, front face, with a plurality of points equidistant from each other and the center of the bit, the back face of said bit having radial flat ribs at the central portion connected to said points by inclined radial ribs. 14. A chain cutter comprising the combination with a bit holding link, of a bit having a substantially triangular body the corners of which define cutting points with V-shaped cutting edges and having its rear surface provided with curved radial ribs extending from the center of the body to the cutting points and having its front substantially fiat in a single plane, reinforcements between each rib and the next adjacent rib, a bit holder including spaced portions one of which is provided with a recess conforming to the contour of the rear surface of the bit and receiving a portion of the body of the bit for supporting the bit in predetermined position with respect to the longitudinal axis of the bit holcier, and

means for holding the bit in a predetermined adjustment .in the said recess.

15. As a new article of manufacture, a bit for a chain cutter. having a substantially triangular body, the corners of which define cutting points and having one surface provided with radial ribs extending from the center of the body to the aoseawe cutting points with reinforcements between the points at the central portion of the body.

16. A bit holder comprising a pair of co-operating clamping members adapted to engage and clamp a, bit between them, an open ended transverse seat for one of said clamping members, the

clamping member engaging such seat being recessed on its front side to fit the contour of the rear surface of the bit, the other clamping member snugly fitting against the front face of the bit, and interlocking means on the clamping members to prevent relative rotation thereof during cutting operations.

17. A cutter chain, having a plurality of identical cutter bit links andconnecting links, the cutter bit links having off-set bit carrying heads assembled in the chain some as right-handed heads and others as left-handed heads, means comprising transverse seats on said heads inclined differently on successive heads relative to the path of travel of the chain and associated with each of said heads for confining the cutter bit to any one 01 at least three diiferent positions through a range of 60 variation relative to the median plane of mechanism for clamping the cutter bit to its head while said confining means locks the cutter bit at its adjusted angle.

18. A cutter chain for mining machines comprising a plurality of bit holding links and connecting links, each of said bit holding links having a bit carrying head, means comprising a plurality of relatively narrow transverse inclined seats on said heads and distributed along the chain at various angles relative to the median plane of the chain to confine the cutter bits each at a predetermined angle relative to its bit carrying head, there being at least three different angular positions for the cutter bits within a range of 60 on a longitudinal axis parallel to said plane, and mechanism for clamping said confining means and said bit to secure the same to said heads.

19. A mining machine cutter chain comprising a plurality of bit holding links and connecting links, each of said bit holding links having a bit carrying head oil-set from the median plane of the chain and provided with a longitudinal bore having an axis parallel to said plane, mechanism comprising transverse seats on said heads at various angles along the chain for confining the bits to occupy predetermined angular positions relative to said heads so that at least three outter bits will be distributed along the chain within a range of 60 relative to said longitudinal axis, and means for clamping said confining means and said bits to said bit holders.

20. A mining machine cutter chain comprising a plurality of bit .holding links and connecting links, each bit holding link having an oifset bit carrying head, means comprising transverse seats on said heads at various angles for mounting the cutter bits one on each head by being confined by such seats to a predetermined angle relative theretoto secure successive positions of the cutter bits for closely adjacent lines of cutting travel at various distances from the median plane of the chain, and mechanism for clamping said confining means and said bits to said heads to hold the bits rigidly connected to the bit holding links for such adjacent lines of travel as those aforesaid.

21. A mining machine chain cutter comprising a plurality of bit holding links and connecting links, each bit holding link having an oil-set bit carrying head, some of the heads being oilthe cutter chain, and v m to the min and others to the left relative to the median planeoi the chain, means comprising transverse seats on said heads successive- 1y at different angles for mounting the cutter bits one on each head by being confined by its seat to a predetermined angle relative thereto to secure successive positions of the cutter bits for closely adjacent lines of cutting travel on both sides oi said plane and at various distances therefrom, and mechanism for clamping said confining means and said bits rigidly connected to said bit holding links for such adjacent lines of travel on both sides of said plane.

22. A mining machine chain cutter comprising a plurality of bit holding links and connecting links, each bit holding link having an ofl-set bit carrying head, means comprising transverse seats on said heads at various angles in intersecting planes for mounting the cutter bits one on each head by being confined by its seat to a predetermined angle relative thereto to secure successive positions of the cutter bits for at least three closely adjacent lines of cutting travel at various distances from the median plane of the chain, and mechanism for clamping said confining means and said bits rigidly to said heads.

23. A mining machine chain cutter comprising a plurality of bit holding links and connecting links, said bit holding links having bit carrying heads, means comprising transverse inclined seats on said heads arranged successively at different angles to confine the bits for closely adjacent lines of cutting travel, and mechanism for clamping the bits and said confining means rigidly to saidv heads.

24. In a chain cutter for mining machines, the combination with a chain comprising a plurality of similarly cast bit holding links all of the same shape and size and each having an oilset bit carrying head, said bit holding links being assembled in the chain with some of the said heads off-set on the left-hand side of the median plane of the chain and others off-set on the right-hand side of said plane, means comprising seats formed by milling transversely across each bit holding link at various angles distributed along the chain on a longitudinal axis parallel to said plane to confine the bits successively to angular positions spaced from each other, and mechanism for clamping said confining means and said bits to said heads one bit to each head.

25. A mining machine chain cutter comprising a bit holding link having a bit carrying extension with a longitudinal screw-threaded opening extending therethrough, a cutting bit, a pair of clamping members for said cutting bit and rotatably associated with one end of said extension, 9, bolt extending through said clamping members and screw-threaded into said opening, and means comprising a transverse seat at one end of said carrying extension for locking the clamping members against rotation relative to said extension.

26. In a chain cutter for mining machines, the combination with a plurality of connected bit holding links,'of right-handed heads on some of the bit holding links and left-handed heads on other bit holding links, relatively narrow transverse inclined seats on said heads successively in spiral formation along the chain with respect to the right-handed heads and successively in spiral formation along the chain with respect to the left-handed heads, and bit holding mechanism on said heads and adjustable on longitudinal axes spaced laterally from a medial plane extending through the path of travel of the 27. In a chain cutter for mining machines, the combination with a chain comprising a plurality of bit holding links some having right-handed heads and others having left-handed heads, of relatively narrow transverse inclined seats on said heads successively at different angles in predetermined formation from one side'of the chain to the other, a plurality of cutter bits one for each head, and means for securing said bits to said seats to hold the same rigidly connected to the said links in the aforesaid formation from one side-of the chain to the other.

28. The combination with a mining machine chain link having spaced extensions with the opening between the same laterally of the chain bers rigidly to said link.

29. The combination with a mining machine chain link having spaced-apart extensions to afford an opening between the same free and unobstructed laterally of the chain, a transverse seat on one of said extensionaa set screw adapted to be screw-threaded through the other extension, a butter bit, a pair of bit clamping members located between said extensions one being adapted to fit said seat and the other to occupy a position to be engaged by said set screw, and means for preventing lateral movement of said clampingimembers when said set screw secures the same rigidly to said link. 1

30. In coal cutting apparatus, the combination with a cutter chain, of a cutter bit said arms in coal cutting position.:

31. In a mining machine chain cutter, the combination with a bit-carrying link, of a bit seat thereon, a multiple pointed bit having at least three arms one for each cutting point, each am adapting the same to be rotatably adjusted, said 34. As an article of manufacture, a clamping ving a perforation adapting the same to be rotatably adjusted from a bit engaging poclamping position.

35. Bit holding mechanism for mining ma chine chain cutters, comprising a clamping mem-V her having rear faces adapted to be seated on a arrangement being such that the first-named seat is in position to resist feeding thrust parallel to the path of travel of the chain cutter and so that said branching seats are in position to resist feeding thrust at right angles to such path of travel.

37. Bit holding mechanism for mining machine chain cutters, comprising a bit having a front projection intermediate the ends thereof at the rear end of said first-named transverse seat, said seats being angularly related and merging into each other.

- 39. As an article of manufacture adapted to form a part of a mining machine chain cutter, a ring-shaped member having a diameter greater than its axial thickness,

ling-shaped member having a fiat bit engaging face inclined to said axis and relative to a plane at right angles to said axis.

40. As an article of manufacture adapted to form a part of a mining machine chain cutter, havinga diameter greater than its axial thickness, the axis of said ringforcing rib extending radially outward to the outer end of said bit engaging face.

41. As an article of manufacture, a bit clamping member for a mining machine chain cutter, having three radiating seats in intersecting planes on one side thereof, and a rearward projection on the back side of said member with a transverse face adapted to rest on an outside depressed transverse seat on a bit carrying link.

42. Bit holding mechanism for mining ma- .chine chain cutters, comprising a bit holding member having on its front side a bit socket consisting of one seat extending radially inward in position to resist feed parallel to the path of travel of the chain cutter, and of outwardly branching seats merging into said first-named seat in positions to resist feed of the active point of the bit at right angles to the path of travel of the chain cutter, said seats being adapted to receive therear side of the bit with its inner portion straddling said branching seats and its outer active cutting point portion fitting said first-named seat.

43. A bit for cutter chains provided with a plurality of cutting points radially disposed andliaving cutting edges extending between said points, the back of said bit having opposing spaced-apart angular faces between each point and the next adjacent point, with such angular faces extending from the central portion of the bit to said cutting edges.

44. A bit for cutter chains having a plurality of spaced-apart cutting points radially disposed and provided with cutting edges between said points, the rear side of said bit having radial ribs each with faces on opposite sides spacedapart from opposing faces on the next adjacent ribs.

45. A chain cutter comprising the combination with a bit holding link, of a bit having a substantially triangular body. the corners of which define cutting points and having its rear side provided with radial ribs extending from the center of the body to such cutting points and each having angular faces on opposite sides spacedapart from opposing faces on the next adjacent ribs, and a bit holder including spaced portions one of which is provided with a recess conforming to'the contour of the rear side of the bit and supporting the bit in an inclined position with respect to the cutting path of travel of the chain cutter.

46. A chain cutter comprising the combination with a bit holding link; of a bit having a substantially triangular body the corners of which define cutting points and having its rear side provided with radial ribs extending from the center of the bit to the cutting points and each having angular faces on opposite sides spacedapart fromopposing faces on the next adjacent ribs, a bit holder including spaced portions one of which is provided with a recess conforming to the contour of the rear side of said bit and receiving a portion of the body of the bit for supporting the bit in an inclined position with respect to the longitudinal axis of the bit holder, and means for holding the bit in a predetermined adjustment in the said recess.

47. In coal cutting apparatus, the combin tion with a cutter chain, of a cutter bit having a plurality of cutter arms adapted to be successively placed in cutting position upon the to receive said projections.

chain, and means upon the chain comprising radial seats in intersecting planes in position to engage the rear side of all of said arms to hold the bit against bodily displacement and at least one of said arms in coal cutting position.

48. In a mining machine chain cutter, the combination with a bit carrying link, of a multiple pointed bit having at least three arms one for each cutting point, and means comprising a bit seat for engaging the bit to hold the same against its seat with one of said cutting points in cutting position and the others branching laterally for location in free and exposed positions out of contact with any part of said means.

49. In a mining machine chain cutter, the combination with a bit carrying link, of a threepointed bit having three arms one for each cutting point, and means comprising three radiating seats for the back of the bit to hold the latter with one point in cutting position and the other two points free and exposed spaced from the sides of said means.

50. In a mining machine chain cutter, the combination with a cutter chain, a triangular cutter bit having three arms one for each cutting point, said cutting points being adapted to be successively placed in cutting position upon the chain, and means upon the chain to engage the rear sides of all of said arms to hold the bit against bodily displacement with one of said arms in coal cutting position and with the cutting points of the other two arms in free and exposed positions spaced from the sides of said means.

51. A multiple bit for cutter chains comprising a plurality of radially disposed spaced-apart cutting points with cutting edges extending between said points, one side of said multiple bit being approximately fiat and the other side being provided with radial ribs extending to said points, each rib having a spaced-apart pair of angularly disposed faces, one pair individual to each rib.

52. A bit for cutter chains having a plurality of spaced-apart cutting points radially disposed and provided with cutting. edges between said points and outlining a symmetrical contour, the back of said bit having a plurality of projections adapted to fit a seat to prevent rotation of said bit when in operation, each of said projections having a spaced-apart pair of flaring faces, one pair individual to each projection, and the front of said bit being substantially flat.

53. A bit for cutter chains having a plurality of spaced-apart radially disposed points connected together by cutting edges substantially outlining a triangular contour, and a plurality of wedge shaped projections from one side of said bit to afford to each projection a pair of spaced-apart flaring surfaces.

54. The combination with a mining machine chain link, of a bit therefore having a plurality of radially disposed cutting points connected by cutting edges substantially outlining a symmetrical contour, wedge shaped projections on one side of said bit radiating from the center thereof to said points, the opposite side of said bit being flat, each wedge shaped projection having a pair of spaced-apart flaring faces, one pair individual to each projection, and clamping means recessed murmurs. 

